Plasma etch process using polymerizing etch gases across a wafer surface and additional polymer managing or controlling gases in independently fed gas zones with time and spatial modulation of gas content

Abstract

A plasma etch process etches high aspect ratio openings in a dielectric film on a workpiece in a reactor having a ceiling electrode overlying the workpiece and an electrostatic chuck supporting the workpiece. The process includes injecting a polymerizing etch process gas through an annular zone of gas injection orifices in the ceiling electrode, and evacuating gas from the reactor through a pumping annulus surrounding an edge of the workpiece. The high aspect ratio openings are etched in the dielectric film with etch species derived from the etch process gas while depositing a polymer derived from the etch process gas onto the workpiece, by generating a plasma in the reactor by applying VHF source power and/or HF and/or LF bias power to the electrodes at the ceiling and/or the electrostatic chuck. The process further includes slowing the deposition rate of the polymer, minimizing etch stop and/or increasing the etch rate in a region of the workpiece typically the center by injecting oxygen or nitrogen and/or high-fluorine containing gas through gas injection orifice in the corresponding region of the ceiling electrode, and adjusting the flow rate of the oxygen or nitrogen and/or high-fluorine containing gas through the gas injection orifice to minimize the difference between profiles and etch depths at the workpiece center and the workpiece periphery.